Senior Software Engineer Backend, Billing

SG - Singapore · 1+ years experience · Full-time · Onsite · Posted Oct 20, 2026

At a glance

Airwallex is the AI-native financial operating system for a real-time, intelligent economy. More than 675,000 businesses, including McLaren Racing, Qantas, SHEIN, and TikTok, use us, directly or through our platform partners, to run their financial operations or build and monetize financial products of their own.
We started in Melbourne in 2015 to build the infrastructure global commerce runs on. We're the regulated backbone behind global payments: not by accident, but by design. A decade plus, 85+ licenses, and a financial infrastructure spanning North America, Europe, the Middle East, and Asia-Pacific.
We're co-headquartered in San Francisco and Singapore, with more than 2,300 people across 27 offices. We hire builders with founder-level energy, people who move fast with good judgment, dig in with real curiosity, and make calls from first principles rather than waiting to be told what to do. Read our operating principles https://www.airwallex.com/en-us/operating-principles to see it in full.

Airwallex’s Billing team is building the next generation of billing infrastructure for Airwallex and the businesses that use our platform.
You’ll help shape the architecture and deliver reliable backend systems that support complex financial workflows.

Lead the planning, design, and implementation of backend systems for Airwallex’s billing platform.
Partner with Product and business teams to understand customer and business needs, shape technical direction, and deliver core functionality.
Build reliable components within a microservices architecture, including systems that support flexible pricing, invoicing, and quote-to-cash workflows.
Own the architecture and development of complex, distributed systems with high concurrency, high availability, and strong financial accuracy.
Introduce practical technologies and engineering approaches that improve how the team builds, operates, and scales billing products.
Raise the bar on engineering quality through clear design practices, coding standards, and constructive technical collaboration.

6+ years of core Java development experience and 5+ years building internet applications, large-scale financial systems, or e-commerce platforms.
1+ year of experience developing payment platforms.
A bachelor’s degree in Computer Science or a related field.
Strong command of Java 8, including multithreading, high concurrency, I/O or NIO, and network communication.
Experience with common design patterns and the design and development of large-scale distributed, high-concurrency, high-load, and highly available systems.
Experience with server-side technologies and with optimising service response and data queries to maintain service quality.
A track record of solving complex engineering problems in production environments.
The ability to work closely with Product and business teams, translate business needs into technical solutions, and make sound architectural decisions.

Experience with international clearing and settlement or foreign exchange transactions.
Fluent English.

You'll work from our Singapore office
You value in-person collaboration and are happy being in the office five days a week.